Magnetic pump

ABSTRACT

A pump device comprising at least two magnetizable members defining in part a fluid chamber disposed therebetween, means for generating magnetic fields of generally uniform flux through said magnetizable members along their respective lengths, whereby the magnetizable members are periodically polarized for attraction toward each other to effect pumping.

Wolford et a1.

United States Patent 1191 1 1 MAGNETIC PUMP [76] Inventors: Earl W. Wolt'ord, 2285 Forest St.,

Boulder, Colo. 80302; Orville P. Frazee, 2744 Teller St., Lakewood,

Colo. 80215 [22] Filed: Sept. 6, 1972 [21] App]. No.: 286,726

[52] U.S. Cl 417/415, 417/419, 310/32, 310/34 [51] Int. Cl. F04b 17/00 [58] Field of Search; 417/415, 419; 310/32, 34

[56] References Cited UNITED STATES PATENTS 2.468.343 4/1949 Parker 310/34 2.472.334 6/1949 McHenry 310/34 2.486.948 11/1949 Hin'chman... 310/34 2.490.505 12/1949 Benjamin 310/34 11] 3,836,289 1451 Sept. 17, 1974 2,495,598 l/1950 Parker 310/34 2,666,153 1/1954 McHenry et a1 2,706,795 4/1955 Dickey 2.833.220 5/1958 Robinson et a1 310/24 3.119.940 1/1964 Pettit et a1. 310/24 3,437,044 4/1969 Sanders et a1. 310/24 3,629,674 12/1971 Brown 417/415 X Primary Examiner-C. J. Husar Attorney, Agent, or Firm-Clarence A. OBrien; Harvey B. Jacobson 14 Claims, 10 Drawing Figures PMENTEB SEP 1 3.836.289

(Fig-6) (Fig.7) I

PAIENIEDSE W H. 3.836.289

WEI 3 OF 3 Fig.9

- 74 COIL84 COIL 86 A.C.or D.C.

MAGNETIC PUMP The present invention is generally related to pumping devices and, more particularly, to a unique magnetically operated fluid pump which may be operated without the use of springs or the like.

In the past, various electromechanical pumping devices have been proposed which operate on the principles of magnetics. Such conventional constructions included the use of magnetostrictive diaphragms or the like which change dimensionally under the influence of magnetic fields. These pumping constructions, however, were limited in the rate of fluid flow which they could sustain. Most commonly used today are the solenoid type pumps which include a piston or magnetic material which is pulled into a magnetic field by a selectively energizable solenoid coil. Movement of the piston is attributable to a reduction in magnetic reluctance, or the air gap, as the piston is moved from its normal position, beyond the confines of the solenoid, to a retracted position within the confines of the solenoids uniform magnetic field. Such structures have required the use of coil compression springs or the like to effect return of the piston to its original position after the solenoid coil is deenergized. The necessity of return springs has presented a problem for years, as the springs tend to weaken or wear with time, ultimately leading to failure of the pump. This is particularly true in applications involving the pumping of corrosive liquids which come in contact with they return springs.

Attempts to solve the spring problem have met with little success. Structures have been proposed which depend upon the forces of gravity to effect piston return. Such, however, greatly limits the rate of volume flow and, as such, is unsatisfactory for most pumping applications. Other proposed structures have been relatively complex in nature and prohibitively expensive to manufacture.

Therefore, it is an object of the present invention to provide a novel magnetic pump device which includes a minimum number of moving parts and provides piston return without the use of springs, or the like.

Another object of the present invention is to provide a unique magnetic pump device comprising magnetizable pistons or members which are subjected to mag netic fields to sequentially effect attraction and repulsion'therebetween to produce reciprocal movement for pumping. I

It is a further-object of the present invention to provide a versatile magnetic pump device including at least two magnetizable pistons each disposed in an axially uniform magnetic field to magnetically polarize the pistons such that they are attracted when the magnetic fields are of additive polarity and repelled when the magnetic fields are of subtractive'polarity.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

FIG. 1 is a perspective view of a first embodiment of the magnetic pump device of the present invention.

FIG. 2 is a longitudinal sectional view of the magnetic pump device shown in FIG. 1 with a schematic diagram of the control circuitry.

FIG. 3 is a diagrammatic illustration of the magnetic field pattern generated when the coils are energized in the same polarity.

FIG. 4 is a diagrammatic illustration of the magnetic field pattern when the coils are energized in opposite polarity.

FIG. 5 is a diagrammatic illustration of the voltage wave forms applied to the magnetic field coils associated with the present invention.

FIG. 6 is a simplified sectional view of the pump device shown in FIG. I and with the coils polarized to effect attraction between the pump pistons.

FIG. 7 is a simplified sectional view of the pump device similar to FIG. 6, but with the coils polarized to effect repulsion of the pistons.

FIG. 8 is a sectional view of a second embodiment of the pump device of the present invention.

FIG. 9 is a sectional view of a third embodiment of the present invention.

FIG. 10 is a sectional view of a fourth embodiment of the present invention with diagrammatic illustrations of the wave forms impressed upon each coil.

Referring now, more particularly, to FIGS. 1 and 2 of the drawings, a first embodiment of the pump device of the present invention is generally indicated by the numeral l0 and, preferably, is of generally cylindrical configuration with a fluid inlet 12 and a fluid outlet 14 at opposite ends. The inlet and outlet are defined by an elongated pipe or tubular member 16, preferably, of nonmagnetic material. A pair of magnetic field coils l8 and 20 are mounted around tubular member 16 and are generally concentric therewith. Preferably, each coil is woundin a configuration commonly referred to as a solenoid" capable of generating a generally uniform magnetic field through its center, as hereinafter explained. The coils are mounted in close axial proximity to each other and are surrounded by an outer covering of insulation material 22.

A pair of magnetizable members 24 and 26 are mounted in tubular member 16 for reciprocation therein. Each magnetizable member is made of magnetic material exhibiting high magnetic permeability and low coercivity, such as mu-metal. The magnetizable members define a pair of axially disposed pistons with a fluid chamber 28 formed therebetween. Inlet and outlet ports to fluid chamber 28 may be provided in the form of axial bores 30 and 32 extending through pistons 26 and 24, respectively. In addition, the pistons are provided with one-way valves, diagrammatically indicated at 34 and 36, disposed in bores 30 and 32, respectively. The one-way valves may be of a conventional type which are automatically opened and closed under the influence of fluid flow, whereby fluid is permitted to flow in a single direction as indicated by arrows 38.

It will be appreciated that as pistons 24 and 26 are moved toward each other, the volume of fluid chamber 28 is significantly reduced. This forces fluid through one-way valve 36, as one-way valve 34 is closed. Subsequent displacement of the pistons away from each other, is effective to increase the volume of chamber 28 accompanied by closure of valve 36 and opening of valve 34, whereby additional fluid is drawn into the chamber. Thus, continued reciprocation of the pistons provides pumping of the fluid through tubular member 16 in a direction as indicated by arrows 38. Of course, it is not intended that the present invention be limited valves do not necessarily have to be associated with the pistons, and other valving' arrangements may be provided so long as'the volume of the fluid chamber is appropriately changed to effect pumping.

Magnetic field coils I8 and are connected to an appropriate control circuit generally indicated by-the numeral 40. In the embodiment of the invention illustrated in FIG. 2, this circuitry is provided with a conventional full wave rectifier 42 connected across coil 20 and serially connected to a source of alternating current 44 through an adjustable potentiometer 46. Field coil l8'is connected to current source 44 through potentiometer 46, such that the normal sinusoidal voltage is impressed on the coil. This circuit arrangement, in effect, periodically reverses the relative polarity of coils l8 and 20 to effect periodic repulsion of the magnetizable members. Preferably, the magnetic field coils areof greater length than the associated magnetizable members, such that the magnetizable members remain in substantially uniform magnetic fields'at all times during their reciprocation. Of course, it should be understood that magnetic fields may assume various configurations and each may vary somewhat instrength along each path of the associated piston travel so long as the polar affect of each'piston is sufficiently strong to control reciprocation of the other, as explained above. It will also be appreciated that potentiometer is not an essential component of the present invention and, as such, it maybe eliminated or replaced by other well known current controls to effect feedback control or the like.

With particular reference to FIGS. 3 and 4, the magnetic field patterns generated by the coils may be ob served. The magnetic field configuration generated by conventional solenoidcoils is well documented. Generally, the field is most concentrated through the opening in the solenoid, extending axially therethrough curving outwardly around the ends to define an oval-like con figuration. The direction of the magnetic-flux is deter- I mined by the direction of current flow through the coil windings; this characteristic commonly being referred to as polarity. A reversal in the direction of current flow through the coil is accompanied by a corresponding reversal in the direction of the generated magnetic field. With the current flow being into the paper, as indicated by the X-symbol 48, and out of the paper, as indicated by the dot symbol 50, the magnetic field through the center of each coil will point to the left, as shown in FIG. 3. With both coils 18 and 20 in close proximity to each other, and connected in additive polarity, or with current flow in the same direction, the magnetic fields of the coils will add vectorially to provide a general overall configuration as illustrated in FIG. 3. If 60 Hz. current is applied to both coils connected in additive polarity, the direction of the magnetic field will reverse 120 times per second.

With reference to FIG. 4, it will be observed that the magnetic field configuration is significantly changed when the coils are energized in the opposite polarity. However, the magnetic field within the confines of the opening of each coil remains subst antially uniform along the axial length of the opening. B and B are of approximately the same magnitudes as the resultant field through the coil openings when the coils were energized in additive polarity, as illustrated in FIG. 3. This is due to the fact that the field generated by coil 18 has little effect upon the resultant field in the opening of coil 20 and vice versa. I

The reversal of relative polarity between the coils may be effected in many ways. One such means is by way of a full wave rectifier across one of the coils to cause a polarity reversal every half cycle. FIG. 5 illustrates the voltage wave forms impressed upon each of the field coils, with sinusoidal voltage 52 being applied to coil 20. Full wave rectification of the sinusoidal wave form provides a wave form 54 which is applied to coil 18. It will be 'appreciatedthat during the negative half of sine wave 52, wave 54 is positive, such that the polarity of coil 18 is opposite that of coil 20 to produce magnetic fields as illustrated in FIG. 4.

With reference to FIGS. 6 and 7, the above described coaction between the magnetizable pistons may be explained in more detail. It is essential to note that the pistons, or at least the magnetizable portions thereof, remain in generally uniform fields at all times. That is to say, that the movement of either piston is not attributable to a change in magnetic reluctance, as is the case with conventional solenoid devices. Assuming that the pistons are spaced apart as shown in FIG. 6, energization of coils l8 and 20 in additive polarity, is effective to magnetize each piston such that the opposite poles are facing each other. This produces an attraction between the pistons which is a function of the field strength. Thus, the pistons are moved toward each other and one-way valve 36 is opened to exhaust fluid from chamber 38. Valve 34 is held closed and the pistons are moved into engagement, or approximate engagement with each other, as shown in dash in FIG. 6. This attraction between the pistons corresponds in time to the first half cycle of wave forms 52 and 54 as shown in FIG. 5. Subsequently, the relative polarities of the field coils are reversed, such that the adjacent ends of the pistons are of the same polarity as illustrated in FIG. 7. This causes repulsion of the pistons which effectsmovement thereof in opposite directions to the positions indicated in dash line in FIG. 7. During this movement, valve 34 is opened, while valve 36 is held closed. This movement would correspond to the second halves of the wave forms shown in FIG. 5 if a full wave rectifier was utilized to effect polarity reversal. It will be appreciated that as the wave forms described above are impressed upon the coils, the pistons continue to reciprocate in the above-described fashion to effect pumping of fluid. Since the return movements of the pistons is dependent upon the polarity reversals, springs, or the like, are not required, as with conventional solenoid devices.

Referring now, more particularly, to FIG. 8 of the drawings, a second embodiment of the present invention is generally indicated by the numeral 56 and is provided with a pair of field coils and control circuitry similar to that of the first embodiment. However, the second embodiment is provided with a single magnetizable piston 58 which is reciprocated in the above-described manner relative to a stationary magnetizable member 60. The operation is substantially the same, with the polarityreversal causing periodic attraction and repulsion between the magnetizable members. The second embodiment may be utilized in applications involving lesser flowrates or where it is deemed advisable to provide only one movable member for the sake of economy, or other reasons.

With reference to FIG. 9, a third embodiment of the present invention is generally indicated by the numeral 62 and is similar to'the first embodiment in that it is provided with a pair of magnetizable pistons 64 and 66 which are mounted for reciprocation relative to each other in substantially uniform magnetic fields. However, the third embodiment is provided with a single coil 68 connected to a voltage source 70 which may be of either alternating or direct current. In addition, a coil compression spring 72 is disposed between the pistons to effect repulsion therebetwe en when the magnetic field is removed or otherwise altered to reduce the forces of attraction between the pistons. Control of the current through coil 68 may be effected by way of mechanical switching or other controls, such being indicated by the numeral 74, connected to voltage source 70. It will be appreciated, that although the embodiment shown in FIG. 9 utilizes a coil compression spring, the principles of operation from a magnetic standpoint are the same as those utilized in the first and second embodiments, as the pistons depend upon movement in a uniform magneticfield to effect attraction therebetween, rather than a reduction of magnetic reluctance principle utilized by conventional solenoid devices.

With particular reference to FIG. 10, it will be observed that a fourth embodiment, generally indicated by the numeral 76 is shown, which includes three separate field coils and pistons 78, 80, and 82 of magnetizable material. The operation of this embodiment is essentially the same as that of the first embodiment. However, with the three-piston arrangement, there is simultaneous attraction and repulsion forces on the center piston 80, such that the force thereon is nearly constant at all times. This operation is achieved by impressing the illustrated voltage wave forms on coils 84, 86, and 88. Thus, as piston 80 is attracted to piston 78, it is simultaneously repelled from piston 82. Such an arrangement provides two fluid chambers 90 and 92 through which the fluid passes during pumping.

From the foregoing description, it will be appreciated that the magnetic device of the present invention provides a unique means of effecting the movement of the piston members in a magnetic field. The pump devices of the present invention may be manufactured with a minimum number of moving parts and without the use of coil compression springs, or the like, as required with conventional magnetic pump devices. It is not intended, of course, that the present invention be limited to the embodiments illustrated in the drawings, as it is possible to provide other coil and/or piston configurations and provide the basic magnetic operations described above. Also, the concepts of the present invention may be employed in compressor applications involving vapors, or the like.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. A device comprising a housing, first and second magnetizable members mounted in said housing and defining in part a fluid chamber therebetween, one-way valve means, inlet and outlet ports communicating through said one-way valve means with said fluid chamber, at least one of said magnetizable members being movable along an axis relative to the other to correspondingly change the volume of said fluid chamber, means for generating a magnetic field of uniform flux through said magnetizable members along said axis of movement, means for periodically altering said magnetic field, first means for controlling the relative direction of said magnetic field, whereby said magnetizable members are attracted to each other when the magnetic field extends in one general direction through the magnetizable members to contract the volume of said fluid chamber, and second means for displacing said one of the magnetizable members to expand said volume of the fluid chamber.

2. The structure set forth in claim 1 wherein said magnetizable members are of high magnetic permeability and low magnetic coercivity.

3. The structure set forth in claim 1 wherein said field generating means includes magnetic field generating coil connected to a voltage source.

4. The structure set forth in claim 3 wherein said second means includes means for reversing the magnetic polarity of one of said coils relative to the other.

5. The structure set forth in claim 4 wherein said voltage source is of alternating current and said means for reversing the magnetic polarities includes rectifier means connected between one of said coils and said voltage source for periodically effecting relative reversal of current through said one coil relative to the other coil.

6. The structure set forth in claim 1 wherein said movable magnetizable member includes a piston mounted for reciprocation in said housing.

7. The structure set forth in claim 6 wherein said inlet port extends through said first magnetizable member, said outlet port extending through said second magnetizable member.

8. The structure set forth in claim 7 wherein said second magnetizable member comprises a piston mounted for reciprocation in said housing.

9. The structure set forth in claim 8 wherein said first and secondmeans each includes a magnetic field generating coil connected to a voltage source.

10. The structure set forth in claim 9 wherein said second means further includes means for reversing the magnetic polarity of one of said coils relative to the other.

11. The structure set forth in claim 10 wherein said voltage source is of alternating current and said means for reversing the magnetic polarities includes rectifier means connected between one of said coils and said voltage source-for periodically effecting relative reversal of current through said one coil relative to the other coil.

along said axis to effect attraction of said pistons and means for periodically effecting repulsion of said pistons from each other including means for altering said uniform flux magnetic field.

13. The structure set forth in claim 12 wherein said inlet port is formed in one of said pistons, said outlet port being formed in the other of said pistons.

14. An electrically operated pump, comprising a tubular member having opposite inlet and outlet ends, at least one piston made of magnetic material reciprocable within the tubular member between limit positions, fluid chamber means volumetrically contracted and expanded in response to reciprocation of the piston between said limit positions, one-way valve means for conducting fluid flow between said inlet and outlet ends of the tubular member through the piston in response to said contraction and expansion of the fluid chamber means, at least one electromagnetic coil mounted externally on the tubular member and extending axially between the limit positions of the piston, an electrical power means connected to said coil for establishing a magnetic field having a flux path of substantially' uniform flux density extending axially through the piston between said limit positions, and control means connected to the power means for periodically altering the strength of said magnetic field to effect reciproca tion of the piston between the limit positions within said axial flux path of uniform flux density. 

1. A device comprising a housing, first and second magnetizable members mounted in said housing and defining in part a fluid chamber therebetween, one-way valve means, inlet and outlet ports communicating through said one-way valve means with said fluid chamber, at least one of said magnetizable members being movable along an axis relative to the other to correspondingly change the volume of said fluid chamber, means for generating a magnetic field of uniform flux through said magnetizable members along said axis of movement, means for periodically altering said magnetic field, first means for controlling the relative direction of said magnetic field, whereby said magnetizable members are attracted to each other when the magnetic field extends in one general direction through the magnetizable members to contract the volume of said fluid chamber, and second means for displacing said one of the magnetizable members to expand said volume of the fluid chamber.
 2. The structure set forth in claim 1 wherein said magnetizable members are of high magnetic permeability and low magnetic coercivity.
 3. The structure set forth in claim 1 wherein said field generating means includes magnetic field generating coil connected to a voltage source.
 4. The structure set forth in claim 3 wherein said second means includes means for reversing the magnetic polarity of one of said coils relative to the other.
 5. The structure set forth in claim 4 wherein said voltage source is of alternating current and said means for reversing the magnetic polarities includes rectifier means connected between one of said coils and said voltage source for periodically effecting relative reversal of current through said one coil relative to the other coil.
 6. The structure set forth in claim 1 wherein said movable magnetizable member includes a piston mounted for reciprocation in said housing.
 7. The structure set forth in claim 6 wherein said inlet port extends through said first magnetizable member, said outlet port extending through said second magnetizable member.
 8. The structure set forth in claim 7 wherein said second magnetizable member comprises a piston mounted for reciprocation in said housing.
 9. The structure set forth in claim 8 wherein said first and second means each includes a magnetic field generating coil connected to a voltage source.
 10. The structure set forth in claim 9 wherein said second means further includes means for reversing the magnetic polarity of one of said coils relative to the other.
 11. The structure set forth in claim 10 wherein said voltage source is of alternating current and said means for reversing the magnetic polarities includes rectifier means connected between one of said coils and said voltage source for periodically effecting relative reversal of current through said one coil relative to the other coil.
 12. A fluid handling device comprising a housing, a pair of magnetizable pistons reciprocally mounted in said housing for movement along an axis, said pistons defining in part a fluid chamber therebetween, inlet and outlet ports, one-way valve means for establishing communication between said ports and said fluid chamber, each of said pistons being movable away from each other to increase the volume of said fluid chamber, means for periodically generating a magnetic field of substantially uniform flux through said pistons along said axis to effect attraction of said pistons and means for periodically effecting repulsion of said pistons from each other including means for altering said uniform flux magnetic field.
 13. The structure set forth in claim 12 wherein said inlet port is formed in one of said pistons, said outlet port being formed in the other of said pistons.
 14. An electrically operated pump, comprising a tubular member having opposite inlet and outlet ends, at least one piston made of magnetic material reciprocable within the tubular member between limit positions, fluid chamber means volumetrically contracted and expanded in response to reciprocation of the piston between said limit positions, one-way valve means for conducting fluid flow between said inlet and outlet ends of the tubular member through the piston in response to said contraction and expansion of the fluid chamber means, at least one electromagnetic coil mounted externally on the tubular member and extending axially between the limit positions of the piston, an electrical power means connected to said coil for establishing a magnetic field having a flux path of substantially uniform flux density extending axially through the piston between said limit positions, and control means connected to the power means for periodically altering the strength of said magnetic field to effect reciprocation of the piston between the limit positions within said axial flux path of uniform flux density. 